President Trump has claimed that he's "like, really, really smart" and "has all the best words." But a new analysis says: Nuh-uh.

The study finds that Trump communicates at a fourth-grade level — the lowest of the last 15 presidents, dating back to Herbert Hoover, reports Newsweek.

The Factbase database took the first 30,000 words spoken by each president and ranked them on the Flesch-Kincaid grade-level scale and over two dozen tests that measure English-language skill level. Trump was found to be the most simplistic speaker since Harry Truman, who communicated at almost a sixth-grade level.

The most linguistically complex presidents were Hoover and Jimmy Carter, who spoke at a nearly 11th-grade level. Barack Obama was third, with a ninth-grade syntax.

Factbase published the results yesterday, in response to the president's claim over the weekend that he is a "very stable genius."

Last week, Michael Wolff's bombshell new book "Fire and Fury" alleged that most members of Trump's inner circle question his mental and emotional fitness for the presidency. Wolff reported that the president does not read or research the material on which he is making decisions because of a prohibitively short attention span. The book quotes various advisers and people close to Trump as calling him a "dope" and "dumb." In October, NBC reported that Secretary of State Rex Tillerson called Trump a "moron" in a meeting at the Pentagon.

Slapping back at the book, on Saturday Trump tweeted that he had won the presidency on his "first try" and said "I think that would qualify as not smart, but genius....and a very stable genius at that!” He added that “throughout my life, my two greatest assets have been mental stability and being, like, really smart."

Factbase has analyzed Trump's speech before. In August, the company evaluated four decades of Trump's speaking patterns and found that he is most stressed when thanking people and talking about God. The company found Trump displayed the most comfort when talking about infrastructure, the Middle East, war and "The New York Times."